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"Coral-Lation" -- The Discovery Files

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Researchers at Oregon State University for the first time have confirmed some of the mechanisms by which overfishing and nitrate pollution can contribute to the destruction of coral reefs.

Credit: NSF/Karson Productions

Audio Transcript:

"The slippery slope to slime"

I'm Bob Karson with the discovery files--new advances in science and engineering from the National Science Foundation.

(Sound effect: underwater sounds) Corals--one of the planet's oldest lifeforms--host to thousands of species of fish and other animals--are in decline all over the world. In recent decades, reefs in the Caribbean have dwindled by as much as 80%. And that sounds like "reef madness" to me.

A team of researchers led by Oregon State University has confirmed some of the mechanisms behind the degradation--those that start with overfishing and nitrate pollution. These human-created circumstances promote the growth of a large species of algae: Macroalgae. Overfishing reduces populations of large algae-eating fish. While pollution from sewage increases nitrate levels and effectively feeds the macroalgae.

The reefs become overgrown with the algae. Oxygen is choked off, and the growth of helpful bacteria is disrupted. The algae can also introduce foreign pathogens detrimental to the coral. Covered with a green slime, the reefs begin to die off.

The best solution, the researchers say: Reduce the amount of polluting nitrates and curb the overfishing, so a natural balance can restore itself. Our actions can give reefs a chance to recover, now that we've confirmed that, when it comes to humans and reef damage--there's a definite "coral-lation."

"The discovery files" covers projects funded by the government's national science foundation. Federally sponsored research--brought to you, by you! Learn more at or on our podcast.

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